//robotsParser.java
//-------------------------------------
//part of YACY
//(C) by Michael Peter Christen; mc@anomic.de
//first published on http://www.anomic.de
//Frankfurt, Germany, 2004
//
//This file ist contributed by Alexander Schier
//last major change: $LastChangedDate$ by $LastChangedBy$
//Revision: $LastChangedRevision$
//
//This program is free software; you can redistribute it and/or modify
//it under the terms of the GNU General Public License as published by
//the Free Software Foundation; either version 2 of the License, or
//(at your option) any later version.
//
//This program is distributed in the hope that it will be useful,
//but WITHOUT ANY WARRANTY; without even the implied warranty of
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
//GNU General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with this program; if not, write to the Free Software
//Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
//Using this software in any meaning (reading, learning, copying, compiling,
//running) means that you agree that the Author(s) is (are) not responsible
//for cost, loss of data or any harm that may be caused directly or indirectly
//by usage of this softare or this documentation. The usage of this software
//is on your own risk. The installation and usage (starting/running) of this
//software may allow other people or application to access your computer and
//any attached devices and is highly dependent on the configuration of the
//software which must be done by the user of the software; the author(s) is
//(are) also not responsible for proper configuration and usage of the
//software, even if provoked by documentation provided together with
//the software.
//
//Any changes to this file according to the GPL as documented in the file
//gpl.txt aside this file in the shipment you received can be done to the
//lines that follows this copyright notice here, but changes must not be
//done inside the copyright notive above. A re-distribution must contain
//the intact and unchanged copyright notice.
//Contributions and changes to the program code must be marked as such.
package de.anomic.data;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Date;
import de.anomic.http.httpHeader;
import de.anomic.http.httpc;
import de.anomic.plasma.plasmaCrawlRobotsTxt;
import de.anomic.plasma.plasmaSwitchboard;
import de.anomic.server.logging.serverLog;
/*
* A class for Parsing robots.txt files.
* It only parses the Deny Part, yet.
* *
* http://www.robotstxt.org/wc/norobots-rfc.html
*/
public final class robotsParser{
/*public robotsParser(URL robotsUrl){
}*/
/*
* this parses the robots.txt.
* at the Moment it only creates a list of Deny Paths
*/
public static ArrayList parse(File robotsFile) throws IOException {
BufferedReader reader = null;
try {
reader = new BufferedReader(new FileReader(robotsFile));
return parse(reader);
} finally {
if (reader != null) try{reader.close();}catch(Exception e){}
}
}
public static ArrayList parse(byte[] robotsTxt) throws IOException {
if ((robotsTxt == null)||(robotsTxt.length == 0)) return new ArrayList(0);
ByteArrayInputStream bin = new ByteArrayInputStream(robotsTxt);
BufferedReader reader = new BufferedReader(new InputStreamReader(bin));
return parse(reader);
}
public static ArrayList parse(BufferedReader reader) throws IOException{
ArrayList deny = new ArrayList();
int pos;
String line = null;
boolean rule4Yacy = false;
while ((line = reader.readLine()) != null) {
line = line.trim();
if (line.length() == 0) {
// we have reached the end of the rule block
rule4Yacy = false;
} else if (line.startsWith("#")) {
// we can ignore this. Just a comment line
} else if ((!rule4Yacy) && (line.startsWith("User-agent:"))) {
// cutting off comments at the line end
pos = line.indexOf("#");
if (pos != -1) {
line = line.substring(0,pos);
}
// getting out the robots name
pos = line.indexOf(" ");
if (pos != -1) {
String userAgent = line.substring(pos).trim();
rule4Yacy = (userAgent.equals("*") || (userAgent.toLowerCase().indexOf("yacy") >=0));
}
} else if (line.startsWith("Disallow:") && rule4Yacy) {
pos = line.indexOf(" ");
if (pos != -1) {
// getting the path
String path = line.substring(pos).trim();
// unencoding all special charsx
path = URLDecoder.decode(path,"UTF-8");
// escaping all occurences of ; because this char is used as special char in the Robots DB
path = path.replaceAll(";","%3B");
// adding it to the pathlist
deny.add(path);
}
}
}
return deny;
}
public static boolean containsRobotsData(URL nexturl) {
// generating the hostname:poart string needed to do a DB lookup
String urlHostPort = nexturl.getHost() + ":" + ((nexturl.getPort()==-1)?80:nexturl.getPort());
urlHostPort = urlHostPort.toLowerCase();
// doing a DB lookup to determine if the robots data is already available
plasmaCrawlRobotsTxt.Entry robotsTxt4Host = plasmaSwitchboard.robots.getEntry(urlHostPort);
// if we have not found any data or the data is older than 7 days, we need to load it from the remote server
if ((robotsTxt4Host == null) || (robotsTxt4Host.getLoadedDate() == null) ||
(System.currentTimeMillis() - robotsTxt4Host.getLoadedDate().getTime() > 7*24*60*60*1000)) {
return false;
}
return true;
}
public static boolean isDisallowed(URL nexturl) {
if (nexturl == null) throw new IllegalArgumentException();
// generating the hostname:poart string needed to do a DB lookup
String urlHostPort = nexturl.getHost() + ":" + ((nexturl.getPort()==-1)?80:nexturl.getPort());
urlHostPort = urlHostPort.toLowerCase().intern();
plasmaCrawlRobotsTxt.Entry robotsTxt4Host = null;
synchronized(urlHostPort) {
// doing a DB lookup to determine if the robots data is already available
robotsTxt4Host = plasmaSwitchboard.robots.getEntry(urlHostPort);
// if we have not found any data or the data is older than 7 days, we need to load it from the remote server
if (
(robotsTxt4Host == null) ||
(robotsTxt4Host.getLoadedDate() == null) ||
(System.currentTimeMillis() - robotsTxt4Host.getLoadedDate().getTime() > 7*24*60*60*1000)
) {
URL robotsURL = null;
// generating the proper url to download the robots txt
try {
robotsURL = new URL(nexturl.getProtocol(),nexturl.getHost(),(nexturl.getPort()==-1)?80:nexturl.getPort(),"/robots.txt");
} catch (MalformedURLException e) {
serverLog.logSevere("ROBOTS","Unable to generate robots.txt URL for URL '" + nexturl.toString() + "'.");
return false;
}
Object[] result = null;
boolean accessCompletelyRestricted = false;
byte[] robotsTxt = null;
String eTag = null;
Date modDate = null;
try {
serverLog.logFine("ROBOTS","Trying to download the robots.txt file from URL '" + robotsURL + "'.");
result = downloadRobotsTxt(robotsURL,5,robotsTxt4Host);
if (result != null) {
accessCompletelyRestricted = ((Boolean)result[0]).booleanValue();
robotsTxt = (byte[])result[1];
eTag = (String) result[2];
modDate = (Date) result[3];
} else if (robotsTxt4Host != null) {
robotsTxt4Host.setLoadedDate(new Date());
plasmaSwitchboard.robots.addEntry(robotsTxt4Host);
}
} catch (Exception e) {
serverLog.logSevere("ROBOTS","Unable to download the robots.txt file from URL '" + robotsURL + "'. " + e.getMessage());
}
if ((robotsTxt4Host==null)||((robotsTxt4Host!=null)&&(result!=null))) {
ArrayList denyPath = null;
if (accessCompletelyRestricted) {
denyPath = new ArrayList();
denyPath.add("/");
} else {
// parsing the robots.txt Data and converting it into an arraylist
try {
denyPath = robotsParser.parse(robotsTxt);
} catch (IOException e) {
serverLog.logSevere("ROBOTS","Unable to parse the robots.txt file from URL '" + robotsURL + "'.");
}
}
// storing the data into the robots DB
robotsTxt4Host = plasmaSwitchboard.robots.addEntry(urlHostPort,denyPath,new Date(),modDate,eTag);
}
}
}
if (robotsTxt4Host.isDisallowed(nexturl.getPath())) {
return true;
}
return false;
}
private static Object[] downloadRobotsTxt(URL robotsURL, int redirectionCount, plasmaCrawlRobotsTxt.Entry entry) throws Exception {
if (redirectionCount < 0) return new Object[]{Boolean.FALSE,null,null};
redirectionCount--;
boolean accessCompletelyRestricted = false;
byte[] robotsTxt = null;
httpc con = null;
long downloadStart, downloadEnd;
String eTag=null, oldEtag = null;
Date lastMod=null;
try {
downloadStart = System.currentTimeMillis();
plasmaSwitchboard sb = plasmaSwitchboard.getSwitchboard();
//TODO: adding Traffic statistic for robots download?
if ((sb.remoteProxyConfig == null) || (!sb.remoteProxyConfig.useProxy())) {
con = httpc.getInstance(robotsURL.getHost(), robotsURL.getPort(), 10000, false);
} else {
con = httpc.getInstance(robotsURL.getHost(), robotsURL.getPort(), 10000, false, sb.remoteProxyConfig);
}
// if we previously have downloaded this robots.txt then we can set the if-modified-since header
httpHeader reqHeaders = new httpHeader();
if (entry != null) {
oldEtag = entry.getETag();
reqHeaders = new httpHeader();
Date modDate = entry.getModDate();
if (modDate != null) reqHeaders.put(httpHeader.IF_MODIFIED_SINCE,httpc.dateString(entry.getModDate()));
}
httpc.response res = con.GET(robotsURL.getPath(), reqHeaders);
if (res.status.startsWith("2")) {
if (!res.responseHeader.mime().startsWith("text/plain")) {
robotsTxt = null;
serverLog.logFinest("ROBOTS","Robots.txt from URL '" + robotsURL + "' has wrong mimetype '" + res.responseHeader.mime() + "'.");
} else {
// getting some metadata
eTag = res.responseHeader.containsKey(httpHeader.ETAG)?((String)res.responseHeader.get(httpHeader.ETAG)).trim():null;
lastMod = res.responseHeader.lastModified();
// if the robots.txt file was not changed we break here
if ((eTag != null) && (oldEtag != null) && (eTag.equals(oldEtag))) {
serverLog.logFinest("ROBOTS","Robots.txt from URL '" + robotsURL + "' was not modified. Abort downloading of new version.");
return null;
}
// downloading the content
robotsTxt = res.writeContent();
con.close();
downloadEnd = System.currentTimeMillis();
serverLog.logFinest("ROBOTS","Robots.txt successfully loaded from URL '" + robotsURL + "' in " + (downloadEnd-downloadStart) + " ms.");
}
} else if (res.status.startsWith("304")) {
return null;
} else if (res.status.startsWith("3")) {
// getting redirection URL
String redirectionUrlString = (String) res.responseHeader.get(httpHeader.LOCATION);
redirectionUrlString = redirectionUrlString.trim();
// generating the new URL object
URL redirectionUrl = new URL(robotsURL, redirectionUrlString);
// returning the used httpc
httpc.returnInstance(con);
con = null;
// following the redirection
serverLog.logFinest("ROBOTS","Redirection detected for robots.txt with URL '" + robotsURL + "'." +
"\nRedirecting request to: " + redirectionUrl);
return downloadRobotsTxt(redirectionUrl,redirectionCount,entry);
} else if (res.status.startsWith("401") || res.status.startsWith("403")) {
accessCompletelyRestricted = true;
serverLog.logFinest("ROBOTS","Access to Robots.txt not allowed on URL '" + robotsURL + "'.");
} else {
serverLog.logFinest("ROBOTS","robots.txt could not be downloaded from URL '" + robotsURL + "'. [" + res.status + "].");
robotsTxt = null;
}
} catch (Exception e) {
throw e;
} finally {
if (con != null) httpc.returnInstance(con);
}
return new Object[]{new Boolean(accessCompletelyRestricted),robotsTxt,eTag,lastMod};
}
}